For anyone skimming this thread and who is in danger of being taken in by this post, the poll was carried out by ICM. They work to an established, published, peer-reviewed methodology. More importantly they rely on their reputation to stay in business.
Read more here and download the raw data if you want (yes they even publish that) - http://
www.icmunlimited.com/polls/
Read about the same poll on Reuters if you don't like the Express -
http://uk.mobile.reuters.com/article/idUKKCN0Y01OM?irpc=932
Oh, and the question asked was exactly the same one that the referendum itself will use.